Problem: Simplify the following expression: $10\sqrt{80}$.
Explanation: First, try to factor a perfect square out of the radical. $= 10\sqrt{80}$ $= 10\sqrt{16 \cdot 5}$ Separate the radical and simplify. $= 10\sqrt{16} \cdot \sqrt{5}$ $= 10 \cdot 4 \cdot \sqrt{5}$ $= 40\sqrt{5}$